CARSON, Calif. — Sounders FC was clinging for its playoff life, desperate for a goal against the Los Angeles Galaxy, and none of its three designated players were on the field.

Fredy Montero and Christian Tiffert, amid underwhelming performances Sunday, had each been subbed out midway through the second half, and Mauro Rosales was once again out with an injury for crucial moments of the postseason.

The absence of Seattle’s three playmakers for the final minutes of a 3-0 loss in the first leg of the Western Conference finals was particularly noticeable in contrast to the success of Los Angeles’ three DPs.

Robbie Keane was the headliner for the reigning MLS Cup champions with two goals and an assist in the win at The Home Depot Center. Landon Donovan was threatening all night in the attack and earned his 20th career postseason assist. David Beckham’s contributions were more understated, with a consistent work rate and dangerous service on crosses.

“At the end of the day, Robbie Keane and Landon Donovan were very dynamic and were a lot more dynamic than maybe our team was up front on the day,” said Sounders coach Sigi Schmid.

So does he think he’s been getting enough out of his DPs?

“Well, there’s DPs, and DPs,” said Schmid, likely a reference to status and salary.

Keane, Donovan and Beckham each boast more than 100 appearances for their national teams and earn guaranteed compensations of $3.4 million, $2.4 million and $4 million, respectively.

Montero, Tiffert or Rosales don’t boast much, if any, national team experience, and collect guaranteed compensations of, in order, $756,000, $625,000 and $225,000.

The DP rule — implemented in conjunction with MLS’s signing of Beckham in 2007 — is a mechanism that allows teams to spend in excess of the league’s salary cap of $2,810,000.

But for Schmid, money isn’t the main consideration when comparing DPs with L.A.

“I’m talking more about the experience level,” he said of the Galaxy trio. “You’re talking about guys who have 100 caps, each of them. You’re talking about guys who have played in World Cups. You’re talking about guys who’ve played in European Champions League games and things like that. There’s a quality that they’ve been able to express onto the team. For us right now, we’re still searching maybe a little bit for that. I don’t think we’re that far away.”

Keane, for example, has four playoff goals in his past 160 minutes — the same total Sounders FC has in its entire postseason history of 840 minutes.

When asked if the Sounders need to open up their wallet a bit more and sign players like that, particularly if they are to compete with the star-studded Galaxy, Schmid said: “No comment.”

The biggest postseason frustrations in Seattle rest with Montero. The franchise’s leading scorer has been shut out in each of his nine playoff games, a drought of 756 minutes.

Montero does have assists on two of the Sounders’ four postseason goals, but he has managed just two shots in three playoff games this year. His task was most difficult Sunday, playing as a lone forward against a physical Galaxy defense.

“We were doing what the coach wanted, and unfortunately we couldn’t hold the ball or score,” Montero said.

“Every single game I try to do as much as I can, but at the end of the day soccer is played in the midfield.”

Asked if Montero’s drought has become mental, Schmid said: “Hopefully not. He’s pretty good that way, but I’m sure at some point you start thinking about it.”

Another disappointing playoff performance Sunday has provided the Sounders a lot to think about, it seems.

Note

• Mario Martinez was called up by the Honduran national team for a friendly Wednesday against Peru. The game will be played at BBVA Compass Stadium in Houston. Martinez is scheduled to return to Seattle on Thursday. The Sounders are required to release the midfielder for a 48-hour period because the friendly falls during a FIFA window for international games.